The present invention relates to milking equipment and, more particularly, to devices and methods for improving control of the milking cycle and the disinfecting and cleaning of teats and teat cups post-milking.
Conventionally, milking equipment installed in a milking parlor comprises a milking point at each animal stall within the parlor. Each milking point includes a milking cluster of teat cups for connecting the equipment to the teats of an animal to be milked. In the case of cows, for example, each milking cluster has four teat cups. Each teat cup comprises a hollow shell supporting a flexible liner which has a barrel portion for engaging about a teat and, at its upper end, has a head portion with a mouth through which the teat is engaged with the barrel of the liner. At the opposite, discharge end of the teat cup, the liner communicates with a flexible, short milk tube connected to a, so called, clawpiece of the cluster where the milk extracted from the animals teats is collected and delivered, via a flexible, long milk tube, to the collection vessel of the equipment.
Upon commencement of milking, a vacuum is applied to the teat cups, via the long milk tube, the clawpiece and the short milk tubes, for the purposes of extracting milk from the teat cups. This vacuum also leaks between the barrel of the liner and the engaged teat and is applied to a void formed about the teat in the head of the liner in order to capture the cup on the teat. Milking is achieved by automatically and alternately applying vacuum and atmospheric pressure pulses to the space between the shell and the liner of each teat cup in order to flex the liner and stimulate discharge of milk from the engaged teat. It is customary to apply these pneumatic pulses alternately to pairs of teat cups of a cluster. The clawpiece includes a distributor for distributing the pneumatic pulses to the individual teat cups, via flexible pneumatic, lines or tubes.
After completion of a milking cycle, the milking cluster at each milking point is withdrawn from the teats (commonly referred to as “take-off”) such as by an automatic cluster remover and, in a cleansing cycle, the teat cups are flushed internally with disinfectant and water and are dried with compressed air. The teat cups may be fitted with injection nozzles for injecting treatment fluids into the heads of the liners, as described in my copending international application PCT/GB2004/004343, Publication No. WO-A-2005043986. The treatment fluid is fed to the injection nozzles via a distributor of the clawpiece. Alternatively, or in addition, treatment fluids may be supplied to each teat cup via a flush valve connecting the short milk tube to the discharge end of the teat cup. In either event, upon take-off, the milking cluster is designed to enable the short milk tubes to fall away from the centreline of the cluster so that the teat cups are inverted and hang with their heads downwardly from the clawpiece in a rest position. Flushing may be performed with the teat cups in this rest position. Consequently liquid can escape through the head portions of the teat cups. However, where the teats and teat cups are treated with disinfectant fluid and the teat cups are rinsed, there is a risk that the fluids used may contaminate the harvested milk if they are not physically prevented from entering the short milk tube. My copending international application No. PCT/GB2005/000310, Publication No. WO-A-2005072516, describes a shut-off valve device for preventing entry of treatment fluid into the milk tubes and consequent contamination of the harvested milk when, subsequent to milking, treatment fluid is injected into a teat cup to cleanse the cup and teat of an animal and/or to back flush the teat cup.
EP-A-0945057 describes a teat cup which is provided with a cleaning and/or disinfecting device comprising three spraying elements disposed about the upper edge of the teat cup so as to spray fluid obliquely upwards. Before the teat cup is connected automatically to a teat of an animal to be milked, it is positioned under the teat and cleaning fluid is sprayed against the teat by the spraying elements. After the teat has been cleaned, the teat cup is automatically connected to the teat, whereupon milking is started. After the udder quarter of which the teat constitutes part has been milked out, the teat cup is automatically withdrawn and at the same time disinfecting fluid is sprayed against the teat by means of the spraying elements.
Where injection nozzles are used for injecting treatment fluid into the heads of the liners, post-milking, as described in WO-A-2005043986, there is a risk that the treatment fluid may not be supplied in a timely manner to the teat cups and that the charge of air purged from the delivery lines into the teat cups ahead of the treatment fluid may blow the teat cups off the teats.